gpu: ion: Fix several issues with page pool
Split out low and high mem pages so they are correctly reported
when the shrinker is called.
Fix potential deadlock caused by holding the page pool lock while
allocationg and also needing that lock from the shrink function
Change-Id: Iaeb45e5d644f1a1a39b491a2941ee9403fff81f0
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
Git-commit: 27182f504ce9fa7b10cb2520e8684f7c17bc8c86
Git-repo: https://android.googlesource.com/kernel/common
[lauraa@codeaurora.org: Context differences due to debugfs.
Dropped the debugfs support until we can properly sync back
up]
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/drivers/gpu/ion/ion_page_pool.c b/drivers/gpu/ion/ion_page_pool.c
index 04c861a..45b8d7b 100644
--- a/drivers/gpu/ion/ion_page_pool.c
+++ b/drivers/gpu/ion/ion_page_pool.c
@@ -55,24 +55,36 @@
if (!item)
return -ENOMEM;
item->page = page;
- list_add_tail(&item->list, &pool->items);
- pool->count++;
+ if (PageHighMem(page)) {
+ list_add_tail(&item->list, &pool->high_items);
+ pool->high_count++;
+ } else {
+ list_add_tail(&item->list, &pool->low_items);
+ pool->low_count++;
+ }
return 0;
}
-static struct page *ion_page_pool_remove(struct ion_page_pool *pool)
+static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high)
{
struct ion_page_pool_item *item;
struct page *page;
- BUG_ON(!pool->count);
- BUG_ON(list_empty(&pool->items));
+ if (high) {
+ BUG_ON(!pool->high_count);
+ item = list_first_entry(&pool->high_items,
+ struct ion_page_pool_item, list);
+ pool->high_count--;
+ } else {
+ BUG_ON(!pool->low_count);
+ item = list_first_entry(&pool->low_items,
+ struct ion_page_pool_item, list);
+ pool->low_count--;
+ }
- item = list_first_entry(&pool->items, struct ion_page_pool_item, list);
list_del(&item->list);
page = item->page;
kfree(item);
- pool->count--;
return page;
}
@@ -83,12 +95,15 @@
BUG_ON(!pool);
mutex_lock(&pool->mutex);
- if (pool->count)
- page = ion_page_pool_remove(pool);
- else
- page = ion_page_pool_alloc_pages(pool);
+ if (pool->high_count)
+ page = ion_page_pool_remove(pool, true);
+ else if (pool->low_count)
+ page = ion_page_pool_remove(pool, false);
mutex_unlock(&pool->mutex);
+ if (!page)
+ page = ion_page_pool_alloc_pages(pool);
+
return page;
}
@@ -98,9 +113,9 @@
mutex_lock(&pool->mutex);
ret = ion_page_pool_add(pool, page);
+ mutex_unlock(&pool->mutex);
if (ret)
ion_page_pool_free_pages(pool, page);
- mutex_unlock(&pool->mutex);
}
static int ion_page_pool_shrink(struct shrinker *shrinker,
@@ -111,30 +126,38 @@
shrinker);
int nr_freed = 0;
int i;
+ bool high;
+
+ if (sc->gfp_mask & __GFP_HIGHMEM)
+ high = true;
if (sc->nr_to_scan == 0)
- return pool->count * (1 << pool->order);
+ return high ? (pool->high_count + pool->low_count) *
+ (1 << pool->order) :
+ pool->low_count * (1 << pool->order);
- mutex_lock(&pool->mutex);
- for (i = 0; i < sc->nr_to_scan && pool->count; i++) {
- struct ion_page_pool_item *item;
+ for (i = 0; i < sc->nr_to_scan; i++) {
struct page *page;
- item = list_first_entry(&pool->items, struct ion_page_pool_item, list);
- page = item->page;
- if (PageHighMem(page) && !(sc->gfp_mask & __GFP_HIGHMEM)) {
- list_move_tail(&item->list, &pool->items);
- continue;
+ mutex_lock(&pool->mutex);
+ if (high && pool->high_count) {
+ page = ion_page_pool_remove(pool, true);
+ } else if (pool->low_count) {
+ page = ion_page_pool_remove(pool, false);
+ } else {
+ mutex_unlock(&pool->mutex);
+ break;
}
- BUG_ON(page != ion_page_pool_remove(pool));
+ mutex_unlock(&pool->mutex);
ion_page_pool_free_pages(pool, page);
nr_freed += (1 << pool->order);
}
pr_info("%s: shrunk page_pool of order %d by %d pages\n", __func__,
pool->order, nr_freed);
- mutex_unlock(&pool->mutex);
- return pool->count * (1 << pool->order);
+ return high ? (pool->high_count + pool->low_count) *
+ (1 << pool->order) :
+ pool->low_count * (1 << pool->order);
}
struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order)
@@ -143,8 +166,10 @@
GFP_KERNEL);
if (!pool)
return NULL;
- pool->count = 0;
- INIT_LIST_HEAD(&pool->items);
+ pool->high_count = 0;
+ pool->low_count = 0;
+ INIT_LIST_HEAD(&pool->low_items);
+ INIT_LIST_HEAD(&pool->high_items);
pool->shrinker.shrink = ion_page_pool_shrink;
pool->shrinker.seeks = DEFAULT_SEEKS * 16;
pool->shrinker.batch = 0;